The EA81 is push rod (I think) so I wouldn't bother. (it is narrow though)
From my measures the EA82 does require some of the shelf either side of the engine bay removed.
I would have a look for the newer EJ series engine- but stick with the SOHC variety, such as the EJ18 (1800) or EJ22 (2200) both are actually narrower than the EA82 but slightly longer- thats ok though as it still looks to fit nicely in a bug.
To clear the air intake you need to either turn the manifold around (and relocate the alternator), use the funky Custom off road intake manifold inverter
http://www.customoffroad.com.au/partFull.asp?partid=33 or cut a hole in your filewall.
The EJ22 has more power than the EA82T stock, if power is a concern. If you'd like a turbo, well the EJ20 turbos require a lot of work to fit- but from all accounts it is apparently well worth the effort
🙂
Good luck with the decision making.
Cheers
Jeremy
......random gibberish for today.......